Abstract

Weight gain during short-term clozapine treatment is well known. It has been reported to correlate with treatment response. The long-term course of weight gain during clozapine treatment has not been well studied. In a sample of 73 mostly schizophrenic patients, we investigated weight change during short- and long-term treatment (up to 90 months) with clozapine and its correlation with treatment response. The patients showed significant weight increase during the first 12 weeks, reaching a significant weight gain by the second week. Responders and non-responders by week 6 or 12, respectively, did not differ in regard to weight gain by those respective weeks. Also, weight gain during the first 8 weeks was not particularly correlated with treatment response after 6 months. Survival analysis revealed that 80% of the patients gained at least 10% weight and about a third of the patients showed an increase of 20% or more. More than half the patients became overweight by 20% or more. The results indicate that weight gain during clozapine treatment is a significant clinical problem with potentially adverse effects to patients. Research into its treatment is needed.